Furnace seal

ABSTRACT

Apparatus for forming an effective high temperature seal between the separable portions of a heating furnace which apparatus is a combination of a cooling jacket, refractory blanket and jacking means.

United States Patent Seeburger Aug. 19, 1975 [54] FURNACE SEAL 2.666.003 1/1954 Dougherty et a1 266/3 2,742,273 4 1956 8k 432 37 [75] Inventor: Thmas seeburge" Hmsbomugh- 2 869.846 1/1959 432/56 Calm 3 160,404 12 1964 Potenzo et a1. 34/242 [73] Assigneez Bethlehem Steel Corporation, 3459410 8/1969 Uban 432/8 Bethlehem, Pa.

Primary ExaminerJohn J. Camby [22] Filed May 1974 Attorney, Agent, or FirmJoseph J. OKeefe; Michael [2l] Appl. No: 470,247 J. Delaney; Anson W. Biggs U.S. Cl. 432/59; 34/242; 432/242 Int. Cl. F27B 9/028; F27D 3/00 Field of Search 432/8, 59, 242; 34/242 References Cited UNITED STATES PATENTS 2/l934 Fruth et al. 432/72 ABSTRACT Apparatus for forming an effective high temperature seal between the separable portions of a heating furnace which apparatus is a combination of a cooling jacket, refractory blanket and jacking means.

4 Claims, 2 Drawing Figures FURNACE SEAL BACKGROUND OF THE INVENTION This invention relates generally to heating or annealing furnaces, as for example furnaces for the continuous heat treatment of steel strip, and more particularly to an improved seal between separable portions of such furnaces.

The high temperatures incident to the processing of products in heating and/or annealing furnaces requires a seal between separable portions thereof, which seal must remain stable throughout the heating cycle. Expensive and intricately formed sand and water seals for such furnaces are well known but are unsatisfactory because of the limited pressure drop across the seal. In a i search for an improved seal flexible sealing membranes have been attempted wherein the flexible elements were forced into tight contact with adjacent surfaces to form a seal. However, flexible membranes, when exposed to furnace temperatures in excess of 2000 F., generally failed.

The use of a flexible membrane as a sealing element is desirable because such a membrane easily conforms to the configuration of an adjacent mating surface to produce an effective seal. Therefore, no special machining of the mating surfaces is required. However, heretofore no flexible seal system which would perform satisfactorily in a high temperature heating furnace, i.e. above about 2000 F., has been developed.

SUMMARY OF THE INVENTION It is a primary object of this invention to provide a durable and effective seal between the separable portions of a heating furnace.

It is another object of this invention to provide a seal between the mating surfaces of the separable portions of a heating furnace wherein the flexible seal of one such portion conforms to irregularities in the mating surface of an abutting portion.

It is a further object of this invention to provide be tween the separable portions of a high temperature heating furnace an economical seal which will withstand the high temperatures within such a furnace.

The instant invention accomplishes these objects by providing apparatus in conjunction with a heating furnace which has upper and lower separable portions. Such apparatus includes a Water or air cooled jacket mounted on the lower end of the upper portion of the furnace forming the mating surface of the upper portion, a flexible high temperature refractory blanket sealing element mounted on the mating surface of the lower or base support portion of the furnace and means for forcing the flexible sealing element into tight contact with the mating surface of the upper portion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a sectional elevation ofa heat treatment furnace incorporating the improved seal of the instant invention; and

FIG. 2 is an enlarged sectional view of a portion of the improved seal showing the apparatus in sealed position.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings for a detailed description of the invention, FIG. 1 is a sectional elevation of continuous strip heating furnace 10 which incorporates the seal of the instant invention, which seal is shown in the retracted position.

Heating furnace 10 comprises an upper portion 11 and a separable lower portion or support base 12. Upper portion 11 is suspended from rail 13 on trolleys 14 for movement into and out of position over support base 12 to facilitate repair and maintenance of the furnace. Cooling jacket 15, fabricated from steel plate, is mounted on the lower end of the upper portion 11 of the furnace and extends peripherally of such portion. The bottom 16 of the jacket 15 forms the mating surface of the joint 18.

Mounted on the upper surface 19 of the base support 12 and extending peripherally thereof is a base plate 20 upon which a first layer 21 of asbestos and a second layer 22 of refractory cloth is mounted, which layers form a high-temperature-res'istant refractory blanket 23. The refractory blanket 23 is anchored by bolts 24 to the base plate 20 and consequently the base support 12.

A framework 25, preferably of structural steel, is located adjacent to and encompasses a portion of the brickwork forming the support base 12. The framework 25 is spaced slightly from such brickwork 12 to permit relative movement to accommodate expansion and contraction of the base.

The refractory blanket 23, which in this embodiment has been described as a first layer of asbestos and a second layer of refractory cloth overlying the first layer, extends outwardly from bolts 24 sufficiently to overlay slightly the base framework 25.

Mounted beneath and engaging the lower surface of the framework 25 are jacking means 26, as e.g. air cylinders, several of which extend peripherally of base 12 and which are adapted to move the framework 25 and the refractory blanket 23 superposed thereupon upward into contact with the mating surface 16 of the furnace upper portion 11. The seal is seen as in FIG. 2 to be complete with the tight contact of the outer portion of the refractory blanket 23 and the mating surface 16 and the upper surface 27 of framework 25 and the inner portion of refractory blanket 23 securely anchored to the brickwork of base support 12. A bed of sand 28 is distributed over the anchor bolts 24 to protect them from deterioration due to the high temperatures in the furnace 10. It is clear that retraction of jacking means 26 will open the seal, as shown in FIG.

The cooling jacket 15 is adapted to use a variety of coolants, as e.g. air or water circulated therethrough. The purpose of the cooling jacket is to maintain the refractory cloth sealing element at a temperature sufficiently low to prevent deterioration thereof. It has been found that use of a water cooled jacket maintains temperatures of 300400 F. in the area of the seal. The close proximity of the cooled jacket to the flexible sealing element keeps it relatively cool, even as the furnace temperatures range as high as 2800-2900 F.

The refractory blanket 23 found to be most effective comprises a first layer 21 of Va inch thick, ordinary 500 F. maximum temperature asbestos superposed by a second layer of a flexible high temperature insulating refractory cloth. as e.g. Fiberfrax, Type L-I44T or Type DL-144TT containing Nichrome insert material, manufactured by the Corborundum Company, Niagara Falls,

N. Y. It will be clear to those skilled in the art that there are many insulating refractory materials that will be equally suitable for use in the instant invention.

The instant invention thus provides an improved furnace seal which combines a cooling jacket with a high temperature refractory blanket tightly contacting the surfaces of the joint in a durable effective and inexpensive seal.

I claim:

1. In a heating furnace having a support base portion and an upper portion in alignment therewith and separable therefrom, an improved seal comprising:

a. a cooling jacket fixedly mounted on the lower end of the upper portion.

a flexible high temperature cloth-like refractory blanket having one end fixedly mounted on the upper surface of the support base and extending freely therefrom toward the outer periphery of the furnace, and

0. means for biasing the other end of the high temperature refractory blanket into contact with the coolin g jacket to form a seal between the cooling jacket and the support base.

2. In a heating furnace an improved seal according to claim I wherein the cooling jacket is water cooled.

3. ln a heating furnace an improved seal according to claim 1 wherein the cooling jacket is air cooled.

4. In a heating furnace having a support base portion and an upper portion in alignment therewith and separable therefrom, an improved seal comprising:

a. a cooling jacket mounted on the upper portion at the lower end thereof,

b. a framework adjacent to and encompassing the outer periphery of the support base,

c. a flexible high temperature cloth-like refractory blanket having one end mounted on the upper surface of the support base and extending freely therefrom toward the outer periphery of the furnace and overhanging the framework, and

d. means mounted on the framework to jacket the framework and place the other end of the refractory blanket against the cooling jacket.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,900,

DATED August 19, 1975 INVENTOR(S) Thomas A. Seeburger It is certified that error appears in the above-identitied patent and that said Letters Patent are hereby corrected as shown below:

Column 3, claim 1, line 15, before "a flexible" subparagraph (b) should be inserted.

Column t, claim t, subparagr'aph (d) the word "jacket" should be -,jack--, in line 20.

Signed and Scaled this sixteenth Day of December 1975 [SEAL] A ttest:

RUTH C. MASON C. MARSHALL DANN Atlesling Officer Commissioner of Pate/11s and Trademarks 

1. In a heating furnace having a support base portion and an upper portion in alignment therewith and separable therefrom, an improved seal comprising: a. a cooling jacket fixedly mounted on the lower end of the upper portion, a flexible high temperature cloth-like refractory blanket having One end fixedly mounted on the upper surface of the support base and extending freely therefrom toward the outer periphery of the furnace, and c. means for biasing the other end of the high temperature refractory blanket into contact with the cooling jacket to form a seal between the cooling jacket and the support base.
 2. In a heating furnace an improved seal according to claim 1 wherein the cooling jacket is water cooled.
 3. In a heating furnace an improved seal according to claim 1 wherein the cooling jacket is air cooled.
 4. In a heating furnace having a support base portion and an upper portion in alignment therewith and separable therefrom, an improved seal comprising: a. a cooling jacket mounted on the upper portion at the lower end thereof, b. a framework adjacent to and encompassing the outer periphery of the support base, c. a flexible high temperature cloth-like refractory blanket having one end mounted on the upper surface of the support base and extending freely therefrom toward the outer periphery of the furnace and overhanging the framework, and d. means mounted on the framework to jacket the framework and place the other end of the refractory blanket against the cooling jacket. 